A namespace is a collection of pages which have content with a similar purpose, i.e. pages where the intended use is the same. Namespaces can be thought of as partitions of different types of information within the same wiki, and keep "real" content separate from user profiles, help pages, etc.

Contents

Pages exist within a namespace, and this can be distinguished using the namespace prefix of a page, which forms part of the title of a page, separated with a colon (:).

For example:

Title

Namespace

Code

Foo

Main

0

Template:Foo

Template

10

Module:Foo

Module

828

The "main namespace" does not have a prefix. Also, pages in the main namespace cannot have names starting with any of the existing namespaces prefixes followed by a colon.

Pages can be moved between namespaces simply by changing the prefix part of their title.

Namespace prefixes can be translated, and aliases can be configured for each (see $wgNamespaceAliases). All namespaces also have a "canonical" prefix, which works on all wikis regardless of configuration. Aliases and canonical names can be used in links, when performing a search, and in the page title with the help of the {{DISPLAYTITLE}} magic word.

Each namespace has a corresponding namespace index. Within the database, the title is split into namespace index and text title, and this is used for storage in the page.page_namespace and page.page_title columns, among others.

Most namespaces have an associated discussion namespace (or "talk" namespace). All discussion namespaces have odd-integer indices, and the discussion namespace index for a specific namespace with index n is n+1. The namespaces with even-integer indices are subject namespaces (note that this is a distinct concept from content namespaces). The subject-talk duality can be explored using the {{SUBJECTPAGENAME}} and {{TALKPAGENAME}}magic words. The <body> tag of pages in talk namespaces has the "ns-talk" CSS class, which might be useful for styling.

2 "virtual" namespaces (one for dynamically generated special pages, and one serving as an alias for direct file links), numbered -1 and -2, respectively. Since these namespaces don't correspond to pages stored in the database, one cannot create or delete pages in these namespaces, and there are no corresponding discussion namespaces.

Each namespace also has a constant derived from its name, with all letters in uppercase, spaces replaced by underscores, and prefixed by "NS_". For example, the constant for the "User talk" namespace is NS_USER_TALK. A complete list can be found in Manual:Namespace constants.